\(\langle \) 6\(\rangle \)  \((S_M^+({\omega }),S_M^-({\omega }))=(1,1)\)  for \(M=N_2({\omega },b)\) 
being non-trivial (cf. Definition 1.8.11 on p.41 of [1]}) with
\({\omega }=e^{\sqrt{-1}{\theta }}\in {\bf U}\backslash {\bf R}\) .
